U.S. Pat. No. 5,231,970 discloses an archery bow limb attachment construction that includes an archery bow limb adapted to be adjustably mounted to a planar mounting surface of a bow handle riser. The bow limb has an outer surface, an inner surface and a slot-shaped opening that extends through the limb between the outer and inner surfaces. A limb bolt washer or bushing has an undersurface in engagement with the outer surface of the limb and a leg that extends through the slot-shaped opening in the limb to prevent rotation of the bushing with respect to the limb. A cap screw has a head received in a conical countersink at the outer surface of the bushing, and a externally threaded shank that extends through the bushing and the slot-shaped opening of the limb into an internally threaded opening in the handle riser. A set screw extends through a lateral opening in the bushing to engage and lock the cap screw in an adjustably threaded position with respect to the bushing, limb and handle riser.
Although the archery bow limb attachment construction disclosed in the noted patent has enjoyed substantial commercial acceptance and success, improvements are desirable. For example, when the set screw in the noted patent is loosened, it can be difficult to adjust the draw weight of the bow limb because of the force required to overcome friction between the bolt head and the bushing. Friction between the bolt head and bushing can cause the bolt head to score the mating surface of the bushing, creating a source of noise while using the bow and becoming progressively harder to adjust the bow draw weight. It is a general object of the present invention to provide an archery bow limb attachment construction that addresses this problem in the prior art.
An archery bow limb attachment construction in accordance with one presently preferred embodiment of the invention includes a limb bolt washer having a flat undersurface opposed to an outer surface on the limb, a leg extending from the undersurface into a non-round opening in the limb to prevent rotation of the limb bolt washer with respect to the limb, a through-opening having a cylindrical countersink at an end opposed to the undersurface, and an internally threaded lateral opening communicating with the through-opening between the countersink and the undersurface. An annular bearing washer has a cylindrical outer periphery received in the countersink of the limb bolt washer, preferably by press fit, and a through-opening having a conical countersink remote from the limb bolt washer. A cap screw has a head received in the conical countersink of the bearing washer and an externally threaded shank that extends through the bearing washer, the limb bolt washer and the archery bow limb into an internally threaded opening in an archery bow handle riser. A set screw in the lateral opening of the limb bolt washer locks the cap screw against rotation with respect to the limb bolt washer.
In a presently preferred embodiment of the invention, there is a base washer disposed between the outer surface of the bow limb and the undersurface of the limb bolt washer. The base washer has a through-opening through which the cap screw shank is received, and a lug received in a pocket on the undersurface of the limb bolt washer to prevent movement and maintain alignment of the base washer with respect to the limb bolt washer. The base washer preferably includes an opening, most preferably a slotted opening at the periphery of the limb bolt washer diametrically opposite from the lug, for receiving the leg that extends from the undersurface of the limb bolt washer. The through-opening in the limb bolt washer preferably is enlarged at the undersurface to accommodate rocking of the cap screw with respect to the limb bolt washer as the bow limb is adjusted with respect to the handle riser, and the through-opening in the base washer preferably is elongated to accommodate rocking of the cap screw with respect to the base washer during such adjustment.